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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package org.omg.CORBA;

/**
 * An object containing the information necessary for
 * invoking a method.  This class is
 * the cornerstone of the ORB Dynamic
 * Invocation Interface (DII), which allows dynamic creation and
 * invocation of requests.
 * A server cannot tell the difference between a client
 * invocation using a client stub and a request using the DII.
 * <P>
 * A <code>Request</code> object consists of:
 * <UL>
 * <LI>the name of the operation to be invoked
 * <LI>an <code>NVList</code> containing arguments for the operation.<BR>
 * Each item in the list is a <code>NamedValue</code> object, which has three
 * parts:
 * <OL>
 * <LI>the name of the argument
 * <LI>the value of the argument (as an <code>Any</code> object)
 * <LI>the argument mode flag indicating whether the argument is
 * for input, output, or both
 * </OL>
 * </UL>
 * <P>
 * <code>Request</code> objects may also contain additional information,
 * depending on how an operation was defined in the original IDL
 * interface definition.  For example, where appropriate, they may contain
 * a <code>NamedValue</code> object to hold the return value or exception,
 * a context, a list of possible exceptions, and a list of
 * context strings that need to be resolved.
 * <P>
 * New <code>Request</code> objects are created using one of the
 * <code>create_request</code> methods in the <code>Object</code> class.
 * In other words, a <code>create_request</code> method is performed on the
 * object which is to be invoked.
 *
 * @see org.omg.CORBA.NamedValue
 */

public abstract class Request {

  /**
   * Retrieves the the target object reference.
   *
   * @return the object reference that points to the object implementation for the method to be
   * invoked
   */

  public abstract org.omg.CORBA.Object target();

  /**
   * Retrieves the name of the method to be invoked.
   *
   * @return the name of the method to be invoked
   */

  public abstract String operation();

  /**
   * Retrieves the <code>NVList</code> object containing the arguments
   * to the method being invoked.  The elements in the list are
   * <code>NamedValue</code> objects, with each one describing an argument
   * to the method.
   *
   * @return the <code>NVList</code> object containing the arguments for the method
   */

  public abstract NVList arguments();

  /**
   * Retrieves the <code>NamedValue</code> object containing the return
   * value for the method.
   *
   * @return the <code>NamedValue</code> object containing the result of the method
   */

  public abstract NamedValue result();

  /**
   * Retrieves the <code>Environment</code> object for this request.
   * It contains the exception that the method being invoked has
   * thrown (after the invocation returns).
   *
   * @return the <code>Environment</code> object for this request
   */

  public abstract Environment env();

  /**
   * Retrieves the <code>ExceptionList</code> object for this request.
   * This list contains <code>TypeCode</code> objects describing the
   * exceptions that may be thrown by the method being invoked.
   *
   * @return the <code>ExceptionList</code> object describing the exceptions that may be thrown by
   * the method being invoked
   */

  public abstract ExceptionList exceptions();

  /**
   * Retrieves the <code>ContextList</code> object for this request.
   * This list contains context <code>String</code>s that need to
   * be resolved and sent with the invocation.
   *
   * @return the list of context strings whose values need to be resolved and sent with the
   * invocation.
   */

  public abstract ContextList contexts();

  /**
   * Retrieves the <code>Context</code> object for this request.
   * This is a list of properties giving information about the
   * client, the environment, or the circumstances of this request.
   *
   * @return the <code>Context</code> object that is to be used to resolve any context strings whose
   * values need to be sent with the invocation
   */

  public abstract Context ctx();

  /**
   * Sets this request's <code>Context</code> object to the one given.
   *
   * @param c the new <code>Context</code> object to be used for resolving context strings
   */

  public abstract void ctx(Context c);


  /**
   * Creates an input argument and adds it to this <code>Request</code>
   * object.
   *
   * @return an <code>Any</code> object that contains the value and typecode for the input argument
   * added
   */

  public abstract Any add_in_arg();

  /**
   * Creates an input argument with the given name and adds it to
   * this <code>Request</code> object.
   *
   * @param name the name of the argument being added
   * @return an <code>Any</code> object that contains the value and typecode for the input argument
   * added
   */

  public abstract Any add_named_in_arg(String name);

  /**
   * Adds an input/output argument to this <code>Request</code> object.
   *
   * @return an <code>Any</code> object that contains the value and typecode for the input/output
   * argument added
   */

  public abstract Any add_inout_arg();

  /**
   * Adds an input/output argument with the given name to this
   * <code>Request</code> object.
   *
   * @param name the name of the argument being added
   * @return an <code>Any</code> object that contains the value and typecode for the input/output
   * argument added
   */

  public abstract Any add_named_inout_arg(String name);


  /**
   * Adds an output argument to this <code>Request</code> object.
   *
   * @return an <code>Any</code> object that contains the value and typecode for the output argument
   * added
   */

  public abstract Any add_out_arg();

  /**
   * Adds an output argument with the given name to this
   * <code>Request</code> object.
   *
   * @param name the name of the argument being added
   * @return an <code>Any</code> object that contains the value and typecode for the output argument
   * added
   */

  public abstract Any add_named_out_arg(String name);

  /**
   * Sets the typecode for the return
   * value of the method.
   *
   * @param tc the <code>TypeCode</code> object containing type information for the return value
   */

  public abstract void set_return_type(TypeCode tc);

  /**
   * Returns the <code>Any</code> object that contains the value for the
   * result of the method.
   *
   * @return an <code>Any</code> object containing the value and typecode for the return value
   */

  public abstract Any return_value();

  /**
   * Makes a synchronous invocation using the
   * information in the <code>Request</code> object. Exception information is
   * placed into the <code>Request</code> object's environment object.
   */

  public abstract void invoke();

  /**
   * Makes a oneway invocation on the
   * request. In other words, it does not expect or wait for a
   * response. Note that this can be used even if the operation was
   * not declared as oneway in the IDL declaration. No response or
   * exception information is returned.
   */

  public abstract void send_oneway();

  /**
   * Makes an asynchronous invocation on
   * the request. In other words, it does not wait for a response before it
   * returns to the user. The user can then later use the methods
   * <code>poll_response</code> and <code>get_response</code> to get
   * the result or exception information for the invocation.
   */

  public abstract void send_deferred();

  /**
   * Allows the user to determine
   * whether a response has been received for the invocation triggered
   * earlier with the <code>send_deferred</code> method.
   *
   * @return <code>true</code> if the method response has been received; <code>false</code>
   * otherwise
   */

  public abstract boolean poll_response();

  /**
   * Allows the user to access the
   * response for the invocation triggered earlier with the
   * <code>send_deferred</code> method.
   *
   * @throws WrongTransaction if the method <code>get_response</code> was invoked from a different
   * transaction's scope than the one from which the request was originally sent. See the OMG
   * Transaction Service specification for details.
   */

  public abstract void get_response() throws WrongTransaction;

};
